Thiophan-3-one and process for the manufacture of same



Patented Oct. 1, 1946 a UNITED STATES PATENT OFFICE THIOPHAN-ZS-ONE ANDPROCESS FOR THE MANUFACTURE OF SALE Paul Karrer, Zurich, Switzerland,assignor to Hoffmann-La Roche Inc., Nutley, N. J a corporation of NewJersey No Drawing. Application March 22, 1943, Serial N0. 480,090. InSwitzerland April 16, 1942 2 Claims.

It has been found that hitherto unknown thicphan-3-ones can bemanufactured from dihalogenated ketones of the formula wherein R1, R2,R3, R4 are selected from the group consisting of hydrogen, alkyl,aralkyl or aryl; and X and X are selected from the group consisting ofhalogen atoms by the action of metal sulfides thereof. The reactiontakes the following course:

The new compounds are to be used for the preparation of therapeuticallyemployable substances. I

Example 10.2 parts by weight of 1-'chloro-4-iodo-butanone-2 aredissolved in 900 parts by volume of alcohol.(1-chloro-4-iodo-butanone-2' may be manufactured by reactingp-iodo-propionic acid with thionyl chloride, transforming thep-iodopropionic acid chloride formed into the diazo ketone with the aidof diazo methane and acting thereupon with dry' gaseous hydrogenchloride; l-chloro 4-iodo-butanone-2 has its melting point at 54 C.) Tothe alcoholic solution is added parts by weight of potassium acetate,heating for twohour on a, water-bath and finally driving ofi the solventin vacuo. By rubbing the solid residue with a little water thethiophan-B-one semicarbazone remains behind in crystalline form and canbe recrystallised from little water. It then shows a melting point of192 C. By acid hydrolysatlon of the semicarbazone free thicphan-3-one isobtained as a liquid.

Iclaim: o

1. Process for the manufacture of thiophan-3- one, comprising condensinglA-dihalogeno-butanone-2 with sodium sulfide, and recovering the y thuformed thiophan-3-one.

2. Thiophan-3-one of the formula ou -co (IE1- (IE2 PAUL KARRER.

